Betting calculators
The maths bookmakers do on your behalf, so you can check it yourself. Free, no signup, no email address.
Implied probability
Implied probability calculator
Turn any odds into the probability they imply, as a percentage, and compare it with your own estimate.
“What chance do these odds say an outcome has?”
Open calculatorRule 4 deduction
Rule 4 calculator
Work out the deduction from a withdrawn horse's price and check your bookmaker settled the bet correctly.
“Why were my returns cut after a non-runner?”
Open calculatorClosing line value
CLV calculator
Compare the price you took against the closing price, with Rule 4 accounted for, to see whether your results come from judgement or luck.
“Did I beat the market, or did I just get lucky?”
Open calculatorBookmaker margin
Overround calculator
Add up the implied probabilities in a market to see the bookmaker's margin, and the odds with that margin removed.
“How much of this price is the bookmaker's cut?”
Open calculatorEach-way returns
Each-way calculator
Work out win and place returns on the doubled outlay, and find out whether a placed selection actually made you money.
“My horse placed — so why am I down?”
Open calculatorLucky 15 returns
Lucky 15 calculator
Settle all 15 lines of a Lucky 15, win only or each way, and see whether one winner covers the total stake.
“One of my four won — so why am I still down?”
Open calculatorLucky 31 returns
Lucky 31 calculator
Settle all 31 lines of a Lucky 31, win only or each way, and see whether one winner covers the total stake.
“One of my five won — so why am I still down?”
Open calculatorKelly stake
Kelly criterion calculator
Work out a stake as a share of your bankroll from the odds and your own win probability, at full, half or quarter Kelly.
“What stake does my own estimate point to?”
Open calculatorTrixie returns
Trixie calculator
Settle all 4 bets of a Trixie, win only or each way, and see which bets returned against the total stake.
“Two of my three won — so what came back?”
Open calculatorYankee returns
Yankee calculator
Settle all 11 bets of a Yankee, win only or each way, and see which bets returned against the total stake.
“Two of my four won — so what came back?”
Open calculatorAcca returns
Accumulator calculator
Settle an accumulator leg by leg, win only or each way, and see what the bet is worth after each leg.
“Three of my four legs won — so why did nothing come back?”
Open calculatorOdds formats
Odds converter
Turn fractional, decimal or American odds into the other two, with the exact fraction and the probability the price implies.
“What is this price in the other odds formats?”
Open calculatorPatent returns
Patent calculator
Settle all 7 bets of a Patent, win only or each way, and see whether one winner covers the total stake.
“One of my three won — so why am I still down?”
Open calculatorLucky 63 returns
Lucky 63 calculator
Settle all 63 lines of a Lucky 63, win only or each way, and see whether one winner covers the total stake.
“One of my six won — so why am I still down?”
Open calculatorClosing line value
CLV tracker
The calculator above works one bet. The CLV tracker page explains how betr.pro records the taken price, the close, and Rule 4 across a UK horse racing and football record.
Open the CLV trackerWhy these three
They cover the three moments a settled bet stops making sense: a non-runner cut your returns, your horse placed and you still lost money, or you want to know whether a good month was skill. Each one is a calculation bookmakers perform silently, and each one is worth being able to check.
The same maths runs inside betr.pro on every bet you track — Rule 4 applied at settlement, each-way legs split correctly, and closing line value measured across your whole record rather than one bet at a time.
One bet at a time only tells you so much
A single calculation answers what happened. Tracking every bet answers whether you are actually any good — with P&L, ROI, and closing line value measured across your full record.
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